portable air conditioner

Questions on how we spend our money and our time - consumer goods and services, home and vehicle, leisure and recreational activities
Post Reply
User avatar
linuxuser
Posts: 1107
Joined: Mon Jan 24, 2011 9:15 pm

portable air conditioner

Post by linuxuser » Sat Jun 23, 2012 8:34 pm

The bedroom that I use as my computer room gets hot. Downstairs is 78F but in this room it is about 88F.

I was thinking about buying a portable air conditioner, but they seem to get bad reviews.

A window air conditioner is unsightly.

Any other options?

Thoughts?

btenny
Posts: 4632
Joined: Sun Oct 07, 2007 6:47 pm

Re: portable air conditioner

Post by btenny » Sat Jun 23, 2012 8:44 pm

Try to change how the AC air flow is distributed in your house from the air ducks so more of the cold air comes out the upstairs air ducks and the room when you have your computer. Maybe close off completely some vents downstairs and open wider the vents in your computer room. Play around with the settings in various rooms so you get more cold air upstairs and less downstairs so the rooms are more equal temperature. I would try doing a lot of adjustments before I bought a second AC unit.

Good Luck
Bill.

User avatar
LadyGeek
Site Admin
Posts: 49337
Joined: Sat Dec 20, 2008 5:34 pm
Location: Philadelphia
Contact:

Re: portable air conditioner

Post by LadyGeek » Sat Jun 23, 2012 8:46 pm

Move your computer downstairs and install a window fan in the bedroom, set to exhaust outside. It will pull air through the house and the hot upstairs air out with it.
Wiki To some, the glass is half full. To others, the glass is half empty. To an engineer, it's twice the size it needs to be.

User avatar
linuxuser
Posts: 1107
Joined: Mon Jan 24, 2011 9:15 pm

Re: portable air conditioner

Post by linuxuser » Sat Jun 23, 2012 8:51 pm

By window fan, do you mean something like http://www.walmart.com/ip/Holmes-Window-Fan/17133777

Are they easy to install?

mackstann
Posts: 210
Joined: Thu May 17, 2012 12:59 am
Contact:

Re: portable air conditioner

Post by mackstann » Sat Jun 23, 2012 9:02 pm

We got a portable AC as a hand-me-down. It works fine.

A cheap window fan like that just slides in the opening of the window. Usually there are accordian-like things on the sides that expand to fit the opening. I used to have one when I was younger and it was better than nothing, but it's no match for a high-power fan, or an AC.
It does not matter how slowly you go so long as you do not stop.

User avatar
LadyGeek
Site Admin
Posts: 49337
Joined: Sat Dec 20, 2008 5:34 pm
Location: Philadelphia
Contact:

Re: portable air conditioner

Post by LadyGeek » Sat Jun 23, 2012 9:22 pm

linuxuser wrote:By window fan, do you mean something like http://www.walmart.com/ip/Holmes-Window-Fan/17133777

Are they easy to install?
That's the general idea. There's no installation, just slip it inside the window frame and slide to fit. Take it out when not needed, E-Z. You might have to put a towel over where you need to cover the gap between the window and the fan.

As mackstann says, it certainly won't replace an air conditioner, but it will get the air moving. The bigger the better, whatever fits. You can also get a second bigger fan and just set it on the floor to help redirect air towards the window fan.
Wiki To some, the glass is half full. To others, the glass is half empty. To an engineer, it's twice the size it needs to be.

Mudpuppy
Posts: 5889
Joined: Sat Aug 27, 2011 2:26 am
Location: Sunny California

Re: portable air conditioner

Post by Mudpuppy » Sat Jun 23, 2012 10:51 pm

I had this issue a few years ago and considered a portable AC. Then I saw a thread on airflow balancing and that turned out to be the problem. In my house, the airflow was imbalanced and mostly going into the family room. This was due to poor design of the duct work (a large lead feeds the three vents in the family room but several small leads feed all the other vents, so the air takes the path of least resistance to the family room). This left the master bedroom sweltering, particularly since the bedroom is west facing.

My duct work also did not come with dampers, so I had the HVAC company install a damper on the family room lead. It took a little tuning, but eventually I got it to where both the master bedroom and the family room are comfortable. If your duct work already has dampers, it might just be a matter of adjusting them. Something to look into at least.

Edit: By the way, the dampers I refer to are not the sliders on the vents in the room. They are installed on the duct work, usually right where it branches off from the main return from the AC. Mine is in the attic, fortunately within arms reach of the attic access door (so fairly easy to reach in and adjust as needed). If your duct work has the same and someone previously closed the damper to that room, no amount of fiddling with the slider on the vent in the room is going to solve the issue.

User avatar
mhc
Posts: 3812
Joined: Mon Apr 04, 2011 10:18 pm
Location: NoCo

Re: portable air conditioner

Post by mhc » Sat Jun 23, 2012 11:01 pm

linuxuser wrote:By window fan, do you mean something like http://www.walmart.com/ip/Holmes-Window-Fan/17133777

Are they easy to install?
I bought two similar fans at HD this year. They work great if you live somewhere where it cools down at night. We were using ours every night instead of the AC until the mountains caught fire. Now we have to keep the windows closed 24/7 and use the AC. Oh well, there is always next year.

Yes, they are easy to put in and take out of the window especially if the windows slide up and down. Side sliders are not quite as nice but still work.

In the summer we close all vents in the basement and most of the ones on the main flow to force more cold air upstairs. That helps.

User avatar
linuxuser
Posts: 1107
Joined: Mon Jan 24, 2011 9:15 pm

Re: portable air conditioner

Post by linuxuser » Sun Jun 24, 2012 7:32 am

Some of the more expensive windows are 1/2 the price of the smallest window A/C units. :annoyed

I did go downstairs and close off most of the vents.

User avatar
SnapShots
Posts: 915
Joined: Wed May 09, 2012 12:39 pm

Re: portable air conditioner

Post by SnapShots » Sun Jun 24, 2012 10:17 am

I'm in the process of remodeling our garage into a multi-purpose room. The Mitsubishi Duel Heat & Air unit has been recommended by a busy contractor who has used them. I've seen one and they are not obtrusive. Mitsubish, also, has an air conditioning unit. Of course, I'd rather have ducted air and heat but not possible. I'm in the process of researching this unit and not making a recommendation yay or nay at this point.

IMO, you might rethink your objection to a window unit. You can get small ones and remove it when not needed. If you're willing to put a fan in the window, why not a window air conditioner? I have an office, separate from my house, where I use one during the summer and enjoy the white noise and my own private away.

Link to the Mitsubishi unit referred to above

http://www.mitsubishicomfort.com/en/con ... t-showcase
the best decision many times is the hardest to do

User avatar
linuxuser
Posts: 1107
Joined: Mon Jan 24, 2011 9:15 pm

Re: portable air conditioner

Post by linuxuser » Sun Jun 24, 2012 10:49 am

Yes, you are right, if I really want a comfortable computer room, I should probably consider a window A/C unit even if does look tacky. :happy
This bedroom is furthest removed from the air conditioning unit.

With regards to the Mitsubishi units, how does "ductless" work? Do you have the indoor units in every room? What connects the outdoor unit to the indoor units?

jebmke
Posts: 8474
Joined: Thu Apr 05, 2007 2:44 pm

Re: portable air conditioner

Post by jebmke » Sun Jun 24, 2012 10:56 am

I have a small Mitsubishi ductless unit for my home office (ducting not possible). The inside unit is mounted on the wall and connected with a coolant line through the exterior wall to the external unit. It is extremely quiet (both inside and outside) and very efficient. The 9600 BTU unit I installed has a SEER of 26.

They are not inexpensive but all the people I talked with recommended the Mitsubishi over other manufacturers.
When you discover that you are riding a dead horse, the best strategy is to dismount.

User avatar
FlyHi
Posts: 169
Joined: Thu Mar 24, 2011 11:32 am

Re: portable air conditioner

Post by FlyHi » Sun Jun 24, 2012 11:58 am

We have two portable A/Cs, an Amana and a Soleus and they both do the job.
“If you want to feel rich, just count the things you have that money can't buy”

Carl53
Posts: 1637
Joined: Sun Mar 07, 2010 8:26 pm

Re: portable air conditioner

Post by Carl53 » Sun Jun 24, 2012 12:46 pm

I had one bedroom at the end of the home that was often too hot/cold. Installed a duct blower booster fan and a switch to the fan in the room needing the assist. Much better than before. Also if you keep it on via a wall switch it will continually circulate air from the duct work and rest of the house to the room even when the AC/furnace is not running.

This link is something like what I bought. The switch and wiring were separate from the fan purchase.

http://www.amazon.com/Tjernlund-Duct-Bo ... B0000AXFP3

User avatar
daytona084
Posts: 835
Joined: Mon Feb 01, 2010 10:47 pm

Re: portable air conditioner

Post by daytona084 » Sun Jun 24, 2012 12:57 pm

Carl53 wrote:I had one bedroom at the end of the home that was often too hot/cold. Installed a duct blower booster fan and a switch to the fan in the room needing the assist. Much better than before. Also if you keep it on via a wall switch it will continually circulate air from the duct work and rest of the house to the room even when the AC/furnace is not running.

This link is something like what I bought. The switch and wiring were separate from the fan purchase.

http://www.amazon.com/Tjernlund-Duct-Bo ... B0000AXFP3
Carl,

I installed 3 of these Tjernlund Duct Booster Fans to help boost the A/C to the 2nd floor. They sure are noisy. I ended up taking them out.

Mudpuppy
Posts: 5889
Joined: Sat Aug 27, 2011 2:26 am
Location: Sunny California

Re: portable air conditioner

Post by Mudpuppy » Sun Jun 24, 2012 12:58 pm

linuxuser wrote:Some of the more expensive windows are 1/2 the price of the smallest window A/C units. :annoyed

I did go downstairs and close off most of the vents.
Again, you want to balance the airflow at the dampers in the ducts themselves, not at the room vents. Room vents are far removed from the main line and can't always cause the desired redirection. The duct dampers are right off the main line, so can greatly redirect air with just slight adjustments. Also, if you have duct dampers and they are mostly closed in the hot rooms, then closing the room vents in the cool rooms can cause a back-pressure situation where air can't escape the duct work as quickly as the AC is pumping it in. This can harm the AC unit and you'll know it's happening if the unit is getting louder when it's on.

To properly balance the airflow, you (or a HVAC company) should check if your duct work has dampers and adjust those accordingly if found. Fiddling with the room vents is never going to be as effective as doing the airflow balance the proper way: at the duct dampers themselves. Here's a brief website from a pro that essentially says the same thing (and also chides us for using the term "vents" for the room outlets, heh): http://askweldin.com/Balancing.html

rfburns
Posts: 438
Joined: Sun Oct 18, 2009 1:55 pm

Re: portable air conditioner

Post by rfburns » Sun Jun 24, 2012 1:31 pm

linuxuser wrote:I did go downstairs and close off most of the vents.
Beware of doing this. Your A/C is sized to move a certain amount of air over the evaporator. Roughly 400 cfm/ton. If you close too many vents it will try and push more air out of the ones that are open, but the static pressure will go up and overall airflow may be less than needed. This leads to a frozen evaporator and loss of cooling. It's OK to experiment, but know what to look for if you do.

Carl53
Posts: 1637
Joined: Sun Mar 07, 2010 8:26 pm

Re: portable air conditioner

Post by Carl53 » Sun Jun 24, 2012 1:50 pm

wjwhitney wrote:
Carl53 wrote:I had one bedroom at the end of the home that was often too hot/cold. Installed a duct blower booster fan and a switch to the fan in the room needing the assist. Much better than before. Also if you keep it on via a wall switch it will continually circulate air from the duct work and rest of the house to the room even when the AC/furnace is not running.

This link is something like what I bought. The switch and wiring were separate from the fan purchase.

http://www.amazon.com/Tjernlund-Duct-Bo ... B0000AXFP3
Carl,

I installed 3 of these Tjernlund Duct Booster Fans to help boost the A/C to the 2nd floor. They sure are noisy. I ended up taking them out.
I just went down to the spare bedroom and flipped it on. Definitely a noticeable noise. About as loud as a box fan on low, but at a lower pitch.

I examined the fan and the one I installed was actually the Suncourt DB200.
http://www.suncourt.com/Inductor_Pro.html
According to the webpage it is 50 Db/2.2 Sones. On a side note, it was actually made in the USA.

User avatar
SnapShots
Posts: 915
Joined: Wed May 09, 2012 12:39 pm

Re: portable air conditioner

Post by SnapShots » Sun Jun 24, 2012 3:10 pm

jebmke wrote:I have a small Mitsubishi ductless unit for my home office (ducting not possible). The inside unit is mounted on the wall and connected with a coolant line through the exterior wall to the external unit. It is extremely quiet (both inside and outside) and very efficient. The 9600 BTU unit I installed has a SEER of 26.

They are not inexpensive but all the people I talked with recommended the Mitsubishi over other manufacturers.
Glad to have feedback on the Mitsubishi ductless units. We are remodeling a two garage into a multi-purpose room. The contractor recommended one of these. I have seen one and experienced it in action, in a large upstairs room addition. The temp was comfortable and the unit so quiet I didn't know it was on.

But, I think for an upstairs bedroom if all I needed was AC, I'd go with a nice window unit. OP, you may not need a very big one. They're not that bad looking.
the best decision many times is the hardest to do

User avatar
linuxuser
Posts: 1107
Joined: Mon Jan 24, 2011 9:15 pm

Re: portable air conditioner

Post by linuxuser » Sun Jun 24, 2012 3:48 pm

SnapShots wrote:But, I think for an upstairs bedroom if all I needed was AC, I'd go with a nice window unit. OP, you may not need a very big one. They're not that bad looking.
ha ha ha

When my mom visited me last year, one of my neighbors had one, and my mom commented on how tacky it was!

No one else has one around here. And that unit was taken down in the fall last year.

User avatar
interplanetjanet
Posts: 2226
Joined: Mon Jan 24, 2011 4:52 pm
Location: the wilds of central California

Re: portable air conditioner

Post by interplanetjanet » Mon Jun 25, 2012 1:23 am

mhc wrote:I bought two similar fans at HD this year. They work great if you live somewhere where it cools down at night. We were using ours every night instead of the AC until the mountains caught fire. Now we have to keep the windows closed 24/7 and use the AC. Oh well, there is always next year.
I have wondered for some time why home HVAC systems that I've had experience with don't seem to have a feature that most every automotive HVAC system does: a recirculate/fresh air intake control.

I live in an area that can get quite hot during the daytime in summer, but usually cools down in the evenings. The normal approach we've taken for years has been to get as much airflow between inside and outside using open windows, fans and the like at night and in the early part of the day, close up the house (and potentially use the A/C) for the hot part of the day, and then to open things up again once the temperature outside falls to close to the temperature we keep it indoors (usually around 80F in the summer). A home HVAC system that could selectively take in fresh air from outside would have the advantage of filtration and automation, it seems as though it could decrease energy bills substantially in some cases and it doesn't seem like the increased cost due to an extra intake duct and a valve would be terribly high. Control logic seems like it would be pretty simple.

Are there systems like this out there? Is there a reason why they're a terrible idea?

-janet

User avatar
magellan
Posts: 3469
Joined: Fri Mar 09, 2007 4:12 pm

Re: portable air conditioner

Post by magellan » Mon Jun 25, 2012 7:58 am

interplanetjanet wrote:A home HVAC system that could selectively take in fresh air from outside would have the advantage of filtration and automation, it seems as though it could decrease energy bills substantially in some cases and it doesn't seem like the increased cost due to an extra intake duct and a valve would be terribly high. Control logic seems like it would be pretty simple.

Are there systems like this out there? Is there a reason why they're a terrible idea?
I do roughly the same thing with fans at night and have also wondered why they don't build ac systems with a fresh air intake.

My guess is that the result would be a largely ineffective system that's far too costly to run for the airflow it delivers. A dedicated whole house fan that's separate from the ac would probably pay for itself in just a season or two vs running the ac fan with an air intake.

I have a 3 ton ac system and the fan has a 250 watt motor (1/3 hp) that delivers 1,200 CFM of airflow. A whole house fan using that same 250 watts could deliver 5,000 CFM. This is apparently because the evaporator coil and ducting system reduce airflow in the ac system. Also, according to a few handy online calculators, my house would need a whole house fan that delivers at least 4,000 CFM to have effective ventilation.

It's amazing to me how hard it is to match the effectiveness (CFM per watt) of a good window fan vs any kind of ducted system. As an example, this $130 window fan delivers almost 3600 CFM with only 170 watts of power. That's around 5 times more airflow per watt than my ac system.

Jim

User avatar
Bengineer
Posts: 490
Joined: Sat Dec 03, 2011 12:25 pm
Location: NC

Re: portable air conditioner

Post by Bengineer » Mon Jun 25, 2012 10:02 am

I looked into the "HVAC pulling in outside air" a bit. For your HVAC to pull in outside air, you need an intake, ducting, a (big) damper that switches from return to outside, and a controller with both inside & outside temperature (& possibly humidity) sensors. A variable-speed blower motor helps with the efficiency. It is possible to incorporate all this reasonably during construction installation. Not so much as a retrofit. I got a quote for ~$4k! This system would basically run whenever the outside air is 5deg. cooler and the house is above setpoint, likely for hours or overnight at low speed. D-I-Y is plausible. The 3-way damper seemed the hardest part to find when I surfed around on the thought.

On ducted HVAC blowers vs fans: The pressure difference is much greater for the ducted system, so it takes more power to move the air. That's why there is a blower vs a fan in an HVAC system.

Something to consider with the house fan: You need to change the air a few times to pull the house temperature down. That's great, but it also pulls in a ton of dust, pollen and so forth. It piles up quickly enough here in the west just with opening the patio doors and windows! I have had the good fortune to live in two areas that cool off in the evenings, usually with a nice breeze and so have gone the manual route so far. If I build a house or do another extensive renovation out here in the west, I'm sure I'll price out something like this. It would be so cool! :o)

User avatar
Rob5TCP
Posts: 3186
Joined: Tue Jun 05, 2007 7:34 pm
Location: New York, NY

Re: portable air conditioner

Post by Rob5TCP » Mon Jun 25, 2012 3:54 pm

Here is a good article on portable A/C
It gives the pros and cons

http://www.epinions.com/content_1119330436?sb=1

Post Reply